Snap rings of the type adapted to be placed on the ends of a rod or pin and adapted to be housed in a circumferencial groove in the end of the pin or rod are commonly applied using pliers of a type particularly designed for such an application. These pliers can grip the free ends of the legs of a snap ring and force them apart sufficiently that the inside generally circular bore of the snap ring is expanded sufficiently that the snap ring can be forced over the end of a cylindrical pin and positioned in a circumferencial groove of the pin. The pliers are then released to permit the snap ring to snap into the circumferencial groove.
In the construction of link chains, it is common that the chain links are joined by hinge pins, with each of the hinge pins held in place by a snap ring positioned on one end of the hinge pin. Due to the large number of hinge pins and snap rings employed in the construction of such a chain there has been a substantial need for an automated apparatus for placing the snap rings onto the ends of the hinge pins.